A plurality of services are defined in a 5G technology, for example, an enhanced mobile broadband (eMBB) service, a massive machine type communications (mMTC) service, an ultra-reliable and low latency communications (URLLC) service, and a positioning service.
Different services have different quality of service (QoS) requirements. For example, different services have different latency requirements and reliability requirements. As such, different services are corresponding to different parameters. In addition, a physical layer channel in the 5G technology mainly includes a plurality of channel types, such as a control channel, a data channel, and a reference signal. Because types and latency requirements of signals transmitted on different types of channels are different, different channels are also corresponding to different subcarrier spacings.
In conclusion, different subcarrier spacings need to be used for both different services on a same channel and different channels of a same service. Consequently, a plurality of subcarrier spacings may exist in a communications system for one UE, and how to accurately determine a subcarrier spacing used for data transmission is extremely important.